This invention relates to the field of personal cooling apparatus of the open loop type as may be used by workers in a heated, contaminated, or otherwise hostile environment.
As was indicated by considerable worry over possible chemical warfare in the 1991 liberation of Kuwait activities in the Middle East, the difficulties associated with a chemical warfare agent and its clean-up remain of concern in the U.S. military. Although a number of existing systems and methods helpful in the performance of this effort have been available and are continuing to evolve, the extreme complexity and compounded human work difficulties attending such efforts continue to stimulate inventive solutions to certain aspects of the problem.
In my previous patent application, Ser. No. 07/548,454 Chemical Warfare Cooling System and Method there is disclosed, for example, a portable cooling apparatus of the closed circuit liquid type which is especially well adapted to extreme environmental conditions and the ultimate in chemical warfare hostility. The cooling apparatus of this prior application, which is currently under secrecy order in the U.S. Patent Office, is especially useful for relief of cleanup worker heat exposure.
The cooling apparatus of this prior patent application and several of the cooling arrangements patented by others-as are cited below herein, are found to be effective in the removing of heat from a working person. The liquid based cooling systems of these inventions, that is systems wherein cooled liquid passing through tubing or the like is brought in close proximity with the skin of a protected person, are however found to have certain significant disadvantages. A principal one of these disadvantages is concerned with the fact that such systems can actually become counter productive with respect to removing heat from a working person. More precisely, the maintenance of a cool skin condition is found to activate a blood flow restricting physiological response in the working person's body and this restricted blood flow-at the cooled skin surface, actually becomes a hindrance to the offloading of heat from the protected person's body. Such a shutdown of the body's normal heat offloading mechanism is clearly undesirable in a personal cooling apparatus.
Several examples of patent activity in the field of maintaining personal environment temperatures are identified in my previous patent application; these patents include the multiple person apparatus of U.S. Pat. No. 4,691,762 of William Elkins et al which involves quick disconnect couplings and individual control units for each person. Also included is the apparatus of U.S. Pat. No. 4,024,730 of Richard L. Bell et al where the warm-up of liquid oxygen or other breathable gas is accomplished by body heat from the cooled individual. Additionally, included in these patents are the personal cooling systems arranged to be borne by the user including the system of U.S. Pat. No. 3,869,871 of A. P. Rybalko et al; the apparatus of U.S. Pat. No. 3,172,454 of Ernst Warncke et al; the apparatus of U.S. Pat. No. 4,405,348 of A. Pasternak; and the apparatus of U.S. Pat. No. 4,807,447 of J. R. Macdonald et al.
Of additional interest with respect to the present invention is the U.S. Pat. No. 4,856,294 of R. P. Scaringe et al which discloses a vest-like structure employing a phase changeable heat transfer material having phase transition temperatures in a selected moderate range; this close change material is also possibly supplemented by the use of ice. Additionally included is the personal comfort conditioner of Donald Tuomi in U.S. Pat. No. 4,905,475 which discloses an electrically powered heater having sources of cool and warm air which are selected by vane apparatus for delivery to the person being assisted.
Also included in this art is the U.S. Pat. No. 4,738,119 of P. R. Zafred which involves a vest-like structure cooled by sublimating carbon dioxide gas for example. The medical treatment vest-like cooling apparatus of Udo Smidt as disclosed in U.S. Pat. No. 4,718,429 wherein cooling is applied to a patient in order to stimulate body consumption of fatty deposits is also of background interest.
Further included in this patent art is the body cooling device of J. F. Jenkins as described in U.S. Pat. No. 4,545,379 which involves a seating apparatus for the user and provides a face cooling air outlet and hand cooling outlets. This patent also discloses a number of earlier body cooling apparatus patents.
Also included this art is U.S. Pat. No. 3,744,555 issued to J. C. Fletcher et al which involves a cooling garment and sensors responsive to the user's skin temperature for controlling the cooling apparatus. Additionally included is the U.S. Pat. No. 3,630,039 of T. Hayashi which discloses a compressor based personal cooling system which employs a vortex separation of air of differing temperatures.
Although each of these examples of previous work in the personal cooling art is of general interest with respect to the present inventions, none of these prior patent arrangements is fully satisfactory for the chemical warfare cleanup environment of the present invention. It is particularly notable that none of these prior personal cooling arrangements has adequately seized upon the advantages to be realized from using the moisture evaporation normal cooling mechanism of the human body in a personal cooling equipment setting. In addition none of these prior patented system is equipped with its own power source to provide power for operation.